For instance, Messi's weekly basic wage was £492,000 (550,000 euros), when according to the model it should have been £217,000 (243,000 euros).

Prof Shamir added that while the 'superstar effect' of highly paid players bring in the fans and contributes to the financial success of the team, increasing salary inequality is shown to have a negative effect on players' performances.

Many fans wonder if these athletes are worth such massive wages and the findings, published in the International Journal of Computer Science in Sport, suggest some are not.

For the study the salary of each player during the 2016-2017 season was compared to a comprehensive set of 55 attributes that reflect each player's skillset.

These included scoring and passing accuracy, aggression and vision as well as speed, acceleration and ball control.

The data were combined into a single computational model that allowed the researchers to compare the earnings and skills of footballers who played in the same positions.

The researchers pointed out the model does not consider many other financial aspects affecting players' salaries such as broadcasting rights and merchandise sales.

Rakitic is also on the overpaid list (Image: AFP)

These aspects can dramatically motivate teams to compete for the services of star players, thus compensating them more generously.

Prof Shamir said: "The wage of a football player is a function of numerous aspects such as the player's skills, performance in the previous seasons, age, trajectory of improvement, personality, and more.

"Analysis of underpaid and overpaid players shows that overpaid players tend to be stronger, but are inferior in their reactions, vision, acceleration, agility, and balance compared to underpaid football players."

The researchers added that if such an objective quantitative method is used as a baseline and players know the key for determining salaries is equal for everyone, it may improve performance.

These methods may also help simplify the negotiation process between the agent, his player and the club, and determine a uniform salary scale.